Method and Apparatus for Sterilizing Containers

ABSTRACT

A method ( 20 ) and apparatus ( 100 ) for sterilizing packaging ( 102 ) is disclosed herein. The method ( 20 ) applies a solution of hydrogen peroxide onto the packaging ( 102 ) and an alkaline solution to react with the hydrogen peroxide to generate hydroxyl radicals to kill microorganism. The use of an alkaline solution allows the sterilization process to proceed at a lower temperature and a faster rate. A solution of sodium hydroxide is the preferred alkaline solution. The temperature of the process is preferably below 100° C.

TECHNICAL FIELD

The present invention is related to a method and apparatus forsterilizing or disinfecting containers. More specifically, the presentinvention relates to a method and apparatus for sterilizing containersat relatively low temperatures.

BACKGROUND ART

Sterilization of food and medicinal packaging is necessary to killmicroorganisms that may be present on the packaging. The failure toproperly sterilize food packaging could lead to contamination of thefood within the packaging, which could lead to sickness and sometimesdeath to a consumer of the food. The food industry has developed variousmethods to sterilize food packaging to create aseptic packaging.

Traditional aseptic packaging is typically sterilized using hydrogenperoxide. As set forth in Title 37 of the Code of Federal Regulations(“CFR”), Section 178.1005, the U.S. Food and Drug Administration (“FDA”)has determined that a hydrogen peroxide solution containing not morethan 35% hydrogen peroxide may be safely used to sterilize polymericfood-contact surfaces. Sterilization using hydrogen peroxide typicallyrequires high temperatures or ultraviolet light to generate hydroxylradicals from the hydrogen peroxide, which in turn inactivate themicroorganisms on the packaging material. The temperature needed togenerate free radicals from the hydrogen peroxide is usually in excessof 65° C. and is frequently in the range of 120-135° C.

Most food packaging is composed of a polymer material such as plasticbottles. The FDA has provided a list of polymer materials that may beutilized with hydrogen peroxide. The list, set forth in 37 CFR178.1005(e), includes ethylene-acrylic acid copolymers, ethylene-carbonmonoxide copolymers, ethylene-methyl acrylate copolymer resins,ethylene-vinyl acetate copolymers, ionomeric resins, isobutylenepolymers, olefin polymers, polycarbonate resins, polyethyleneterephthalate (“PET”), poly-1-butene resins and butane/ethylenecopolymers, polystyrene and rubber modified polystyrene polymers andvinylidene chloride/methyl acrylate copolymers. Sterilization of plasticbottles is difficult at elevated temperatures since the bottles becomequite fluid and deform during the sterilization process. In addition, anextended drying process is required to evaporate the residue of peroxide(35%) which boils at 108° C. Further, some plastic materials like PETbind, adsorb or absorb peroxide making it very difficult to achieve theresidue limit of 0.5 parts per million (“ppm”) for food packagingrequired by the FDA as set forth in 37 CFR 178.1005(d).

One method of sterilization is disclosed in Sizer et al., U.S. Pat. No.5,326,542 for a Method And Apparatus For Sterilizing Cartons, whichdiscloses using ultraviolet light to sterilize food cartons.

Another method is disclosed in Sizer et al., U.S. Pat. No. 5,770,232 fora Method Of Disinfecting The Food Contact Surfaces Of Food PackagingMachines And Disinfecting Solution Therefor, which discloses using asolution of 0.1% to about 1% by weight of hydrogen peroxide and fromabout 0.001% to about 0.1% by weight of sodium acid pyrophosphateapplied at a temperature of about 70° C. for at least fifteen minutes.

Another method is disclosed in Frisk, U.S. Pat. No. 5,928,607 for aBottle Sterilization Method And Apparatus, which discloses usingultraviolet radiation from an excimer lamp to generate ozone from oxygento sterilize plastic bottles.

Another method is disclosed in Lentsch et al., New Zealand Patent Number282691 for a Method For Sanitizing And Destaining Food Ware And UtensilsUsing A Composition Comprising Peroxycarboxylic Acid, Carboxylic Acid,Peroxide And A Carrier, discloses a sanitizing concentrate compositionof 1-20 weight % peroxycarboxylic acid, 10-50 weight % carboxylic acid,3-35 weight % hydrogen peroxide and the balance a carrier.

Yet another method is disclosed in Wang, European Patent Number 0411970for Sterilization Of Containers By Means Of Hydrogen Peroxide, Peracids,And U.V. Radiation, which discloses using between 15 to 25%concentration of hydrogen peroxide and peracetic acid at a temperatureof 20-30° C. with U.V. light at a wavelength of less than 300 nanometersfor 8-12 seconds to effectuate a greater than 6.0 log reduction in thenumber of B. subtilis spores.

Yet another method is disclosed in Smith et al., U.S. Pat. No. 6,479,454for Antimicrobial Compositions And Method Containing Hydrogen PeroxideAnd Octyl Amine Oxide, which discloses using a composition of an amineoxide hydrogen peroxide to sanitize food contact surfaces.

Another method is disclosed in Taggart, U.S. Pat. No. 6,209,591 for anApparatus And Method For Providing Container Filling In An AsepticProcessing Apparatus, which discloses spraying atomized hydrogenperoxide onto bottles within a sterilization chamber that has sterileair present at a temperature of 135° C.

Another method is disclosed in Taggart, U.S. Pat. No. 6,536,188 for aMethod And Apparatus For Aseptic Packaging, which discloses spraying hothydrogen peroxide onto bottles, allowing approximately 24 seconds foractivation and removal of the hydrogen peroxide, and then filling thebottle with a low acid beverage.

Hall, II et al., U.S. Pat. No. 5,344,652 for a Anticorrosive Microbicidediscloses a two part component containing a first part of hydrogenperoxide, peracetic acid and acetic acid, and a second part ofVICTAWET®, which is a sodium hydroxide reaction product of an aliphaticalcohol (2-ethyl hexyl) and phosphorous pentoxide. The VICTAWET® reducesthe corrosiveness of the peroxide/peracetic biocide.

Nystrom et al. U.S. Pat. No. 5,900,111 for a Process For SanitizingPost-Consumer Paper Fibers Using Heat And Hydrogen Peroxide disclosessanitizing waste paper hydrogen peroxide and using sodium hydroxide toadjust the pH of a fiber stream during the sanitizing process.

Japanese Patent Publication Number 02-154763 for a Method For RemovingHydrogen Peroxide discloses removing excess hydrogen peroxide from softcontact lenses subjected to a hydrogen peroxide sterilization treatmentby using a removing agent essentially consisting of sodium thiosulfate,sodium pyruvate, peroxidase and a metallic catalyst, with the softcontact lenses also subjected to ultrasonic waves.

Japanese Patent Publication Number 07-291236 for a Method Of SterilizingFood Container discloses using hot water with a germicide forced into aninterior of a food container, with the germicide being hydrogenperoxide, peracetic acid, mixture of hydrogen peroxide and peraceticacid or sodium hypochlorite.

Although the prior art has disclosed many different methods forsterilizing containers, especially food containers, there is still aneed for using hydrogen peroxide at low temperatures in an expeditedmanner in order to reduce costs, increase container filling productivityand most importantly adequately sterilize the containers.

SUMMARY OF THE INVENTION

The present invention provides a solution to the need for a lowtemperature sterilization process. The present invention is able toaccomplish this by using a two component solution of hydrogen peroxideand an alkaline solution. The alkaline solution quickly reacts withhydrogen peroxide to generate active oxygen species including hydroxylradicals to destroy microorganisms.

One aspect of the present invention is a method for sterilizingpackaging. The method begins by applying a hydrogen peroxide solutionhaving from 1% to 50% hydrogen peroxide to packaging. The hydrogenperoxide solution is applied at a temperature ranging from 35° C. to100° C. Next, the hydrogen peroxide solution is permitted to activate onthe packaging for an activation period of at least about one second.Next, an alkaline solution is applied to the packaging subsequent to theactivation period. The alkaline solution has a pH in the range of 10-14.The alkaline solution is applied at a temperature ranging from 35° C. to100° C. Next, the packaging is rinsed with sterile water to remove theresidue alkaline solution and residue hydrogen peroxide.

Another aspect of the present invention is a method for sterilizing aplastic bottle. The method beings with applying a hydrogen peroxidesolution having from 30% to 40% hydrogen peroxide to an exterior surfaceof the plastic bottle and an interior surface of the plastic bottle. Thehydrogen peroxide solution is applied at a temperature ranging from 40°C. to 60° C. Next, the hydrogen peroxide solution is permitted toactivate on the exterior surface of the plastic bottle and the interiorsurface of the plastic bottle for an activation period ranging from 1second to 10 seconds. Next, a solution of 0.25 Normal sodium hydroxideis applied to the exterior surface of the plastic bottle and theinterior surface of the plastic bottle subsequent to the activationperiod. The solution of 0.25 Normal sodium hydroxide has a pH in therange of 11-13. The solution of 0.25 Normal sodium hydroxide is appliedat a temperature ranging from 50° C. to 75° C. Next, the packaging isrinsed with sterile water to remove the residue sodium hydroxide andresidue hydrogen peroxide.

Yet another aspect of the present invention is a method for sterilizingpackaging at a low temperature. The method begins by applying a hydrogenperoxide solution having from 1% to 50% hydrogen peroxide to packaging.The hydrogen peroxide solution is applied at a temperature no greaterthan 65° C. Next, the hydrogen peroxide solution is permitted toactivate on the packaging for an activation period ranging from 1 secondto 30 seconds. Next, an alkaline solution is applied to the packagingsubsequent to the activation period. The alkaline solution has a pH inthe range of 10-14. The alkaline solution is applied at a temperature nogreater than 65° C. Next, the packaging is rinsed with sterile water toremove the residue alkaline solution and residue hydrogen peroxide.

Yet another aspect of the present invention is a method for sterilizingpackaging at a low temperature and low temperature aseptic hot fillingof a flowable food product into the packaging. The method begins byapplying a hydrogen peroxide solution having from 1% to 50% hydrogenperoxide to packaging. The hydrogen peroxide solution is applied at atemperature of approximately 60° C. Next, the hydrogen peroxide solutionis permitted to activate on the packaging for an activation periodranging from 1 second to 30 seconds. Next, an alkaline solution isapplied to the packaging subsequent to the activation period. Thealkaline solution has a pH in the range of 10-14. The alkaline solutionis applied at a temperature of approximately 60° C. Next, the packagingis rinsed to remove the residue alkaline solution and residue hydrogenperoxide. Next, the packaging is aseptically hot filled with a flowablefood product at a low temperature ranging from 60° C. to 80° C. Theflowable food product may be orange juice, soup, other juices, and likeflowable food products.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart of a general method of the present invention.

FIG. 2 is a flow chart of a specific method of the present invention.

FIG. 3 is a flow chart of a specific method of the present invention.

FIG. 4 is a flow chart of a specific method of the present invention.

FIG. 5 is a schematic view of containers being sterilized on anapparatus of the present invention.

BEST MODE(S) FOR CARRYING OUT THE INVENTION

As illustrated in FIG. 1, a general method of sterilizing containers,especially food containers, is designated 20. At block 21, a containeris provided for sterilization. The container has interior surfaces andexterior surfaces, with both surfaces preferably requiringsterilization. The container is preferably a food container, althoughother types of containers requiring sterilization such as containers foreye-care products, medical products and the like are within the scopeand spirit of the present invention. Preferably the container iscomposed of a polymer material or glass, although containers composed ofother materials are within the scope and spirit of the presentinvention. A preferred polymer material is PET or high densitypolyethylene.

At block 22, a solution of 1% to 50% hydrogen peroxide is applied to theinterior surfaces and the exterior surfaces of the container. Thehydrogen peroxide solution is preferably applied at a temperatureranging from 35° C. to 100° C., more preferably at a temperature rangingfrom 35° C. to 85° C., even more preferably at a temperature rangingfrom 40° C. to 60° C., and most preferably at a temperature of 50° C. or60° C. The solution of hydrogen peroxide preferably has a concentrationranging from 1% to 50% hydrogen peroxide, more preferably 30% to 40%,and most preferably 35%. The hydrogen peroxide is preferably applied tothe container in a liquid form. Alternatively, the hydrogen peroxide isapplied as a vapor and allowed to condense on the surfaces of thecontainer. The solution of hydrogen peroxide is preferably allowed toremain on the surfaces of the container for an activation time period of30 seconds, more preferably less than 30 seconds, even more preferablyless than 10 seconds, and most preferably one second or less.

After the activation time period, an alkaline solution is applied to thesurfaces of the container as set forth in block 23. The alkalinesolution preferably has a pH ranging from 10 to 14, more preferably from11 to 13, and most preferably 12.5 or 12.9. The alkaline solution ispreferably a sodium hydroxide solution or potassium hydroxide solution.However, those skilled in the pertinent art will recognize that otheralkaline solutions may be utilized without departing from the scope andspirit of the present invention. The alkaline solution is preferablyapplied at a temperature ranging from 35° C. to 100° C., more preferablyat a temperature ranging from 35° C. to 85° C., even more preferably ata temperature ranging from 50° C. to 75° C., and most preferably at atemperature of 65° C. or 60° C. The alkaline solution is preferably a0.05 Normal solution of sodium hydroxide (approximately 0.20%concentration of sodium hydroxide). Alternatively, a one Normal solutionof sodium hydroxide is utilized as the alkaline solution. In yet anotheralternative embodiment, a 0.1 Normal solution of potassium hydroxide isutilized as the alkaline solution. The alkaline solution reacts with thehydrogen peroxide to generate active oxygen species and hydroxylradicals which kill the microorganisms on the surfaces of the container.The alkaline solution lessens the sterilization time to achieve asepticconditions. Further, the alkaline solution decreases the absorption ofhydrogen peroxide by the container and also hydrogen peroxide residue.Yet further, the alkaline solution allows the sterilization process tobe performed at lower temperatures than the prior art sterilizationmethods, which allows for the use of thinner wall containers.

At block 24, the interior surfaces and exterior surfaces of thecontainer are rinsed to remove hydrogen peroxide residue and also anyalkaline solution. Preferably, the surfaces of the container are rinsedwith sterile water, or alternatively an acid rinse such as citric acidor other similar acids. Subsequent to the rinsing, the containers arefilled with a product. Preferably the containers are filled with a foodproduct such as orange juice (high acid product), milk (low acidproduct), water, juices, soups or other similar foods. More preferably,the containers are aseptically hot filled with a flowable food productat a temperature preferably ranging from 60° C. to 70° C. This allowsfor the use of inexpensive thinner wall containers since the lowtemperature hot-filling will not heat distort the containers. Typically,inexpensive thinner wall containers will distort at temperatures ofaround 80° C. or higher.

A more specific sterilization method is illustrated in FIG. 2. Thespecific sterilization method is generally designated 30. At block 31, abottle composed of PET or a PET derivative is provided forsterilization, generally on a filling machine. Most water bottles andorange juice containers are composed of PET or a PET derivative.

At block 32, a solution of 1% to 50% hydrogen peroxide is applied to theinterior surfaces and the exterior surfaces of the container. Thehydrogen peroxide solution is preferably applied at a temperatureranging from 35° C. to 100° C., more preferably at a temperature rangingfrom 35° C. to 85° C., even more preferably at a temperature rangingfrom 40° C. to 60° C., and most preferably at a temperature of 50° C. or60° C. The solution of hydrogen peroxide preferably has a concentrationranging from 1% to 50% hydrogen peroxide, more preferably 30% to 40%,and most preferably 35%. The hydrogen peroxide is preferably applied tothe container in a liquid form. Alternatively, the hydrogen peroxide isapplied as a vapor and allowed to condense on the surfaces of thecontainer. Although there is no upper limit, the solution of hydrogenperoxide is preferably allowed to remain on the surfaces of thecontainer for an activation time period of 30 seconds, more preferablyless than 30 seconds, even more preferably less than 10 seconds, andmost preferably one second or less.

After the activation time period, a solution of sodium hydroxide isapplied to the surfaces of the container as set forth in block 33. Thesodium hydroxide solution preferably has a pH ranging from 10 to 14,more preferably from 11 to 13, and most preferably 12.5 or 12.9. Thesodium hydroxide solution is preferably applied at a temperature ofapproximately 65° C. or approximately 60° C. The sodium hydroxidesolution is preferably a 0.05 Normal solution of sodium hydroxide(approximately 0.20% concentration of sodium hydroxide). Alternatively,a one Normal solution of sodium hydroxide is utilized as the alkalinesolution. The sodium hydroxide solution reacts with the hydrogenperoxide to generate active oxygen species and/or hydroxyl radicalswhich kill the microorganisms on the surfaces of the container. Thesodium hydroxide solution lessens the sterilization time to achieveaseptic conditions. Further, the sodium hydroxide solution decreases theabsorption of hydrogen peroxide by the container and also hydrogenperoxide residue. Yet further, the sodium hydroxide solution allows thesterilization process to be performed at lower temperatures than theprior art sterilization methods, which allows for the use of thinnerwall containers.

At block 34, the interior surfaces and exterior surfaces of the PETbottle are rinsed to remove hydrogen peroxide residue and also anysodium hydroxide solution. Preferably, the surfaces of the container arerinsed with sterile water. Subsequent to the rinsing, the containers arefilled with a product. Preferably the containers are filled with a foodproduct such as orange juice (high acid product), milk (low acidproduct), water, juices, soups or other similar foods. More preferably,the containers are aseptically hot filled with a flowable food productat a temperature preferably ranging from 60° C. to 80° C., and morepreferably from 60° C. to 80° C. This allows for the use of inexpensivethinner wall containers since the low temperature hot-filling will notheat distort the containers. Typically, inexpensive thinner wallcontainers will distort at temperatures of around 80° C. or higher.

An alternative method with a different sequence is illustrated in FIG.3. The method is generally designated 40. At block 41, a bottle composedof PET or a PET derivative is provided for sterilization, generally on afilling machine. Most water bottles and orange juice containers arecomposed of PET or a PET derivative.

A solution of sodium hydroxide is first applied to the surfaces of thecontainer as set forth in block 42. The sodium hydroxide solutionpreferably has a pH of approximately 12.5. The sodium hydroxide solutionis preferably applied at a temperature ranging from 35° C. to 100° C.,more preferably at a temperature ranging from 35° C. to 85° C., evenmore preferably at a temperature ranging from 50° C. to 75° C., and mostpreferably at a temperature of 65° C. or approximately 60° C. The sodiumhydroxide solution is preferably a 0.05 Mole solution of sodiumhydroxide (approximately 0.20% concentration of sodium hydroxide).Alternatively, a one Normal solution of sodium hydroxide is utilized asthe alkaline solution.

At block 43, a solution of 1% to 50% hydrogen peroxide is applied to theinterior surfaces and the exterior surfaces of the container. Thehydrogen peroxide solution is preferably applied at a temperatureranging from 35° C. to 100° C., more preferably at a temperature rangingfrom 35° C. to 85° C., even more preferably at a temperature rangingfrom 40° C. to 60° C., and most preferably at a temperature of 50° C. orapproximately 60° C. The solution of hydrogen peroxide preferably has aconcentration ranging from 1% to 50% hydrogen peroxide, more preferably30% to 40%, and most preferably 35%. The hydrogen peroxide is preferablyapplied to the container in a liquid form. Alternatively, the hydrogenperoxide is applied as a vapor. The sodium hydroxide solution reactswith the hydrogen peroxide to generate hydroxyl radicals which kill themicroorganisms on the surfaces of the container. The sodium hydroxidesolution lessens the sterilization time to achieve aseptic conditions.Further, the sodium hydroxide solution decreases the absorption ofhydrogen peroxide by the container and also hydrogen peroxide residue.Yet further, the sodium hydroxide solution allows the sterilizationprocess to be performed at lower temperatures than the prior artsterilization methods, which allows for the use of thinner wallcontainers.

At block 44, the interior surfaces and exterior surfaces of the PETbottle are rinsed to remove hydrogen peroxide residue and also anysodium hydroxide solution. Preferably, the surfaces of the container arerinsed with sterile water. Subsequent to the rinsing, the containers arefilled with a product. Preferably the containers are filled with a foodproduct such as orange juice (high acid product), milk (low acidproduct), water, juices, soups or other similar foods. More preferably,the containers are aseptically hot filled with a flowable food productat a temperature preferably ranging from 60° C. to 80° C., and morepreferably from 60° C. to 80° C. This allows for the use of inexpensivethinner wall containers since the low temperature hot-filling will notheat distort the containers. Typically, inexpensive thinner wallcontainers will distort at temperatures of around 80° C. or higher.Although plastic containers capable of withstanding higher filltemperatures, typically thicker-walled containers, can be filled up to100° C.

An alternative sterilization method is illustrated in FIG. 4. Thealternative sterilization method is generally designated 50. At block51, a container is provided for sterilization, generally on a fillingmachine. The container is preferably composed of a polyethylene orpolypropylene material. Most milk jugs are composed of polyethylene.

At block 52, a solution of 1% to 50% hydrogen peroxide is applied to theinterior surfaces and the exterior surfaces of the container. Thehydrogen peroxide solution is preferably applied at a temperatureranging from 35° C. to 100° C., more preferably at a temperature rangingfrom 35° C. to 85° C., even more preferably at a temperature rangingfrom 50° C. to 75° C., and most preferably at a temperature of 65° C.The solution of hydrogen peroxide preferably has a concentration rangingfrom 1% to 50% hydrogen peroxide, more preferably 30% to 40%, and mostpreferably 35%. The hydrogen peroxide is preferably applied to thecontainer in a liquid form. Alternatively, the hydrogen peroxide isapplied as a vapor and allowed to condense on the surfaces of thecontainer. Although there is no upper limit, the solution of hydrogenperoxide is preferably allowed to remain on the surfaces of thecontainer for an activation time period of 30 seconds, more preferablyless than 30 seconds, even more preferably less than 10 seconds, andmost preferably one second or less.

After the activation time period, a solution of ferrous sulfate isapplied to the surfaces of the container as set forth in block 53. A oneNormal solution of ferrous sulfate is utilized as the solution. Thesolution of ferrous sulfate is preferably applied at a temperatureranging from 35° C. to 100° C., more preferably at a temperature rangingfrom 35° C. to 85° C., even more preferably at a temperature rangingfrom 40° C. to 60° C., and most preferably at a temperature of 50° C.The ferrous sulfate solution reacts with the hydrogen peroxide togenerate hydroxyl radicals which kill the microorganisms on the surfacesof the container. The ferrous sulfate solution lessens the sterilizationtime to achieve aseptic conditions. Further, the ferrous sulfatesolution decreases the absorption of hydrogen peroxide by the containerand also hydrogen peroxide residue. Yet further, the ferrous sulfatesolution allows the sterilization process to be performed at lowertemperatures than the prior art sterilization methods, which allows forthe use of thinner wall containers.

At block 54, the interior surfaces and exterior surfaces of thecontainer are rinsed to remove hydrogen peroxide residue and also anyferrous sulfate solution. Preferably, the surfaces of the container arerinsed with sterile water. Subsequent to the rinsing, the containers arefilled with a product, preferably as described above.

As shown in FIG. 5, an apparatus for sterilizing containers is generallydesignated 100. Each of a plurality of containers 102 a-c with openings120 to the interior surfaces is preferably transported on a conveyormeans 104 form various stations. In a preferred embodiment, at a firststation 106 hydrogen peroxide is applied to the interior surfaces andexterior surfaces of the container 102 a. At a second station 108, thealkaline solution is applied to the interior surfaces and exteriorsurfaces of the container 102 b. At a third station 110, the interiorsurfaces and exterior surfaces of the container 102 c are rinsed,preferably with sterile water. The conveyor means 104 is preferably aconveyor belt that moves according to the activation period necessaryfor the hydrogen peroxide.

Alternatively, the containers 102 are conveyed upside down to allowgravity to assist in draining the solutions and rinse from thecontainers subsequent to sterilization.

Yet further in an alternative embodiment, each container 102 is placedat a station and dispensers 112 a-c containing or in flow communicationwith the various solutions and rinses are moved over or under thecontainers to dispense each solution or rinse onto the container.

The following examples illustrate the efficacy of the method of thepresent invention. The experiments were designed to identify theconditions optimal for polymer sterilization and also explore theboundary areas to determine the conditions limiting the efficacy of thetreatment. Polymer materials were inoculated with 10⁶ of B. subtilisvar. globigii (ATCC 9372) as set forth in the tables. Each polymer stripwas inoculated by drop spotting approximately 100 micro-liters andcoating the surface by swabbing the surface of the polyethylene strip.The culture was allowed to dry before sterilization. Each strip ofpolyethylene was treated by vigorously agitating the strip in theappropriate treatment solutions. Each treated polymer strip was thentreated with catalase to inactivate residual peroxide, swabbed andplated using TGE incubated at 35° C. for two days.

In Table One, a NaOH control, an inoculated untreated control, and twomethods of the present invention were measured and the results set forthin Table 1. Five replicate polymer strips were used for each of the twomethods of the present invention. A log measurement value is providedbelow each of the non-log values. The first method uses hydrogenperoxide first and then an alkaline solution of sodium hydroxide. Thesecond method uses an alkaline solution of sodium hydroxide first andthen hydrogen peroxide. The sterilization was conducted at 50° C.

TABLE ONE Inoculated 1M NaOH Untreated 35% H₂O₂ + 1M NaOH + ReplicateControl Control 1M NaOH 35% H₂O₂ 1 CFU/Swab 5,700 1,800,000 <10 <101logCFU/Swab 3.76 6.26 <1.00 <1.00 2CFU/Swab 210 2,700,000 <10 <102logCFU/Swab 2.32 6.43 <1.0 <1.0 3CFU/Swab NA 1,600,000 <10 <103logCFU/Swab NA 6.20 <1.00 <1.00 4CFU/Swab NA NA <10 <10 4logCFU/Swab NANA <1.00 <1.00 5CFU/Swab NA NA <10 <10 5logCFU/Swab NA NA <1.00 <1.00

As shown in Table One, the methods of the present invention (the two farright columns) killed the microorganisms. The untreated control had1,800,000 colony forming units (“CFU”) while the methods of the presentinvention successfully sterilized the polymer strips to obtain a valueof <10 CFU. Further, the log reduction of CFU was essentially from log6.26 to <1.0.

TABLE TWO 50° C. 10 s 50° C. 30 s 0.25M 50° C. 30 s 3.5% NaOH + 50° C.10 s 50° C. 30 s 35% H₂O₂ + 50° C. 30 s H₂O₂ + 10 s 35% Inoculated 0.25M35% H₂O₂ 10 s 3.5% H₂O₂ 10 s H₂O₂ + Untreated NaOH 10 s 0.25M 10 s 0.25M10 s Replicate Control Control catalase NaOH catalase NaOH catalase1CFU/Swab 3,200,000 6,300,000 40 30 1,600,000 3,700,000 1,5001logCFU/Swab 6.51 6.80 1.60 1.48 6.20 6.57 3.18 2CFU/Swab 4,900,0003,800,000 570 20 4,200,000 4,200,000 7,900 2logCFU/Swab 6.69 6.58 2.761.30 6.62 6.62 3.90 3CFU/Swab 7,200,000 7,900,000 20 20 4,000,0004,200,000 7,900 3logCFU/Swab 6.86 6.90 1.30 1.30 6.60 6.59 4.234CFU/Swab 3,800,000 5,400,000 270 10 3,000,000 6,100,000 20,0004logCFU/Swab 6.58 6.73 2.43 1.00 6.48 6.79 4.30 5CFU/Swab NA NA 2700 <105,000,000 2,700,000 200,000 5logCFU/Swab NA NA 3.43 <1.00 6.70 6.43 5.30Std Dev. 0.15 0.13 0.86 0.21 0.19 0.13 0.77 Average 6.66 6.75 2.30 1.226.52 6.60 4.18 Log reduction 4.35 5.44 0.14 0.06 2.48

In Table Two, results are presented for a test where the bacteria werespotted, spread on a Petri dish and allowed to dry prior to treatment.The harshness of the sterilization conditions were decreased from theprevious run by reducing the concentration of the alkali treatment andby using stagnant, unagitated solutions The results for the inoculateduntreated control are set forth in column two, results for a 0.25M NaOHcontrol are set forth in column three, results for a solution having 35%H₂O₂ applied and an activation time period of 30 seconds followed by acatalase having an activation period of 10 seconds are set forth incolumn four, results for a solution having 35% H₂O₂ applied and anactivation time period of 30 seconds followed by a solution of 0.25MNaOH having an activation period of 10 seconds are set forth in columnfive, results for a solution having 3.5% H₂O₂ applied and an activationtime period of 30 seconds followed by a catalase having an activationperiod of 10 seconds are set forth in column six, results for a solutionhaving 3.5% H₂O₂ applied and an activation time period of 30 secondsfollowed by application of a solution of 0.25M NaOH having an activationperiod of 10 seconds are set forth in column seven, and the results foran application of a solution of 0.25M NaOH having an activation periodof 10 seconds, then application of a solution having 35% H₂O₂ and anactivation time period of 10 seconds followed by a catalase having anactivation period of 10 seconds are set forth in column eight. A logmeasurement value is provided below each of the non-log values. Thesterilization was conducted at 50° C. The results in Table 2 clearlydefine the synergy of the combined treatment. Column 2 is theinoculated, untreated control having 10̂6.66 bacteria per plate. Column 3represents the survival for treatment with 0.25% sodium hydroxide andclearly shows no bacteriocidal effect. A thirty second hydrogen peroxidetreatment (column 4) results in a 4.35 log inactivation (1.45 log per 10seconds of treatment) while combining peroxide with sodium hydroxide(column 5) results in one log greater inactivation of bacteria. Hydrogenperoxide at 3.5% concentration alone (column 6) and in combination with0.25% sodium hydroxide (column 7) had no effect under these conditions.Pretreatment of the spores with 0.25 M sodium hydroxide in combinationwith a short 10 second treatment with 35% hydrogen peroxide inactivated2.48 logs of bacteria. This rate of kill per unit time was significantlyincreased from the treatment with hydrogen peroxide alone (1.45 logs per10 seconds). Both treatments using the combination of hydrogenperoxide/sodium hydroxide resulted in an order of magnitude increase inthe microbial inactivation. The sterilization method of column five hadthe best results.

In Table Three, a solution of 0.1 Normal potassium hydroxide (KOH) wasutilized with a solution of 3% hydrogen peroxide at a temperature of 35°C. for 30 seconds. The results indicate that the treatment was notefficacious under these conditions of treatment.

TABLE THREE Inoculated Catalase H₂O₂ Untreated 3% H₂O₂ + 0.1N KOH +Replicate Control Control Control 0.1N KOH 3% H₂O₂ 1CFU/Swab 2,500,0005,200,000 2,000,000 8,000,000 2,500,000 1logCFU/Swab 6.40 6.72 6.30 6.906.40 2CFU/Swab NA NA NA 8,900,000 3,100,000 2logCFU/Swab NA NA NA 6.956.49 3CFU/Swab NA NA NA 3,700,000 2,800,000 3logCFU/Swab NA NA NA 6.576.45 4CFU/Swab NA NA NA 3,900,000 4,100,000 4logCFU/Swab NA NA NA 6.596.61 5CFU/Swab NA NA NA 7,100,000 2,800,000 5logCFU/Swab NA NA NA 6.856.45

Graph One and Graph Two illustrate the distortion of plastic bottles hotfilled at three different temperatures, 60° C., 70° C. and 80° C. Thebottle hot filled at 60° C. has very little distortion, and only a 0.43millimeter change in diameter. The bottle hot filled at 70° C. has agreater amount of distortion, with a shrinkage in height and a diameterdistortion of 2.17 millimeters. The bottle hot filled at 80° C. has thegreatest amount of distortion, with a shrinkage in height down to 197.11millimeters, and a diameter distortion of 3.63 millimeters. The presentinvention allows for aseptically hot filling a flowable food product ata temperature preferably ranging from 60° C. to 80° C., and morepreferably from 60° C. to 70° C. This allows for the use of inexpensivethinner wall containers since the low temperature hot-filling will notheat distort the containers as demonstrated in Graphs One and Two. Asdemonstrated in Graphs One and Two, inexpensive thinner wall containerswill distort at temperatures of around 80° C. or higher.

1-25. (canceled)
 26. A method for sterilizing packaging, the methodcomprising: applying a hydrogen peroxide solution having from 1% to 50%hydrogen peroxide to packaging, the hydrogen peroxide solution appliedat a temperature of approximately 60° C. and permitting the hydrogenperoxide solution to activate on the packaging; applying an alkalinesolution to the packaging subsequent to the activation period, thealkaline solution having a pH in the range of 10-14, the alkalinesolution applied at a temperature ranging of approximately 60° C.;rinsing the packaging with sterile to remove the residue alkalinesolution and residue hydrogen peroxide; and hot filling the packagingwith a flowable food product, the packaging filled at a temperatureranging from 60° C. to 80° C.
 27. The method according to claim 26wherein the flowable food product is orange juice.
 28. The methodaccording to claim 26 wherein the alkaline solution is a solution of0.05 Normal sodium hydroxide having a pH of approximately 12.5.
 29. Themethod according to claim 26 wherein the hydrogen peroxide solution hasa concentration of approximately 35% hydrogen peroxide.
 30. The methodaccording to claim 26 wherein the packaging is a PET bottle, apolyethylene bottle or a polypropylene bottle.
 31. A method forsterilizing a plastic bottle, the method comprising: applying a hydrogenperoxide solution having from 30% to 40% hydrogen peroxide to anexterior surface of the plastic bottle and an interior surface of theplastic bottle, the hydrogen peroxide solution applied at a temperatureof approximately 60° C.; permitting the hydrogen peroxide solution toactivate on the exterior surface of the plastic bottle and the interiorsurface of the plastic bottle for an activation period; applying asolution of 0.05 Normal sodium hydroxide to the exterior surface of theplastic bottle and the interior surface of the plastic bottle subsequentto the activation period, the solution of 0.05 Normal sodium hydroxidehaving a pH in the range of 11-13, the solution of 0.05 Normal sodiumhydroxide applied at a temperature of approximately 60° C.; rinsing thepackaging with sterile water to remove the residue sodium hydroxide andresidue hydrogen peroxide; and hot filling the packaging with a flowablefood product, the packaging filled at a temperature ranging from 60° C.to 80° C.
 32. The method according to claim 31 wherein the flowable foodproduct is orange juice.
 33. The method according to claim 31 whereinthe alkaline solution is a solution of 0.05 Normal sodium hydroxidehaving a pH of approximately 12.5.
 34. The method according to claim 31wherein the hydrogen peroxide solution has a concentration ofapproximately 35% hydrogen peroxide.
 35. The method according to claim31 wherein the plastic bottle is a PET bottle, a polyethylene bottle ora polypropylene bottle.
 36. The method according to claim 31 wherein thesolution of hydrogen peroxide is applied as a vapor.
 37. The methodaccording to claim 31 wherein the flowable food product is hot filled ata temperature less than 70° C. without heat distortion of the plasticbottle.
 38. The method according to claim 31 wherein the flowable foodproduct is hot filled at a temperature ranging from 60° C. to 70° C.without heat distortion of the plastic bottle.
 39. An apparatus forperforming the method of claim 26 or claim 31.